photon detector with pbwo4 crystals and apd readout aps
TRANSCRIPT
Photon Detector withPbWO4 Crystals and APD Readout
APS “April” Meetingin
Denver, COon
May 4, 2004
presented by
Kenta Shigaki(Hiroshima University, Japan)
for the
ALICE-PHOS Collaboration
May 4, 2004 Photon Detector with PWO and APD / APS Meeting in Denver / Kenta Shigaki 2
- Presentation Outline -physics via photon channels at LHC-ALICEcalorimeters in relativistic heavy ion experiments• working environments and performance requirements• best scintillation crystal and readout device candidates
basic properties of key components• PbWO4 crystals• avalanche photo diode readout system
prototypes of PbWO4/APD calorimeter• 1st stage prototypes – 3×3 assemblies
• basic properties of PbWO4 crystals and APD readout system• 2nd stage prototype – 16×16 assembly
• ALICE-PHOS performance evaluationsummary and outlook
May 4, 2004 Photon Detector with PWO and APD / APS Meeting in Denver / Kenta Shigaki 3
- Physics via Photon Channels at LHC-ALICE -photons in relativistic heavy ion experiments• vital probes of initial/hot/dense phase of collision system
• direct thermal photons• photon HBT correlations• jet quenching
• experimental virtues• photons and neutral mesons measured in same detector• particle identification to very high transverse momentum
photons: promising though difficult• many interesting physics outcome at RHIC• many more waiting at LHC
• even more powerful tool• large direct photon rate up to ~ 100 GeV• large neutral meson (“background”) suppression
May 4, 2004 Photon Detector with PWO and APD / APS Meeting in Denver / Kenta Shigaki 4
- ALICE Photon Spectrometer -
PHOS: high-granularity high-resolution photon spectrometer• PbWO4 crystals with APD readout• |η| < 0.5, ∆φ ~ 100 degrees, 17,920 channels• photons and neutral mesons• γ-jet tagging
May 4, 2004 Photon Detector with PWO and APD / APS Meeting in Denver / Kenta Shigaki 5
- Calorimeters in Relativistic Heavy Ion Exp. -working environments• high particle multiplicity• high particle spatial density• possibly in (high) magnetic field
performance requirements• high two-cluster separation capability with high granularity• high energy resolution• energy range from ~ 100 MeV to ~ 100 GeV
best scintillation crystal and readout device candidates• PbWO4 (PWO)
• short radiation length• small Moliere radius
• avalanche photo diode (APD)• magnetic-field resistance• compactness
May 4, 2004 Photon Detector with PWO and APD / APS Meeting in Denver / Kenta Shigaki 6
- Basics of PbWO4 Crystals -dense, fast, radiation-hard inorganic scintillator• density: 8.28 g/cm3
• radiation length: 0.89 cm (shortest as known inorganic scintillator)• Moliere radius: 2.2 cm (smallest as known inorganic scintillator)
• suitable for high-granularity calorimeter• refractive index: 2.3
only a few manufacturers available• Furukawa (Japan), North Crystal (Russia), RI&NC (Belarus), …
optical and scintillating properties investigated• transmittance• scintillation light yield
• temperature dependence• scintillation decay time
• ditto
May 4, 2004 Photon Detector with PWO and APD / APS Meeting in Denver / Kenta Shigaki 7
- Japanese PbWO4 Crystals -manufactured by Furukawa, Co.
density 8.28 [g/cm3]radiation length 0.89 [cm]
Moliere radius 2.2 [cm]peak emission 420-440 [ns]
refractive index 2.3
20 x 20 x 200 mm
Y-doped PbWO4
light yield mean decay time
transmittancemeasured withHitachi U3010
spectrophotometer
ALICE-PHOSoperation point
ALICE-PHOSoperation point
May 4, 2004 Photon Detector with PWO and APD / APS Meeting in Denver / Kenta Shigaki 8
- PbWO4 Crystals from Other Manufacturers -RI&NC Co. in Minsk, Belarus• adopted by CMS• investigated; similar properties as Furukawa’s
• ref. graduation thesis by K.Yokoyama(available only in Japanese)
North Crystal Co. in Apatity, Russia• adopted by ALICE-PHOS• further tests at Hiroshima being prepared
May 4, 2004 Photon Detector with PWO and APD / APS Meeting in Denver / Kenta Shigaki 9
- Avalanche Photo Diode Readout System -advantages over conventional PMT readout• magnetic-field resistance• compactness• low power consumption• high quantum efficiency
ALICE-PHOS choices• APD: Hamamatsu S8664 (short wavelength enhanced type)
• basic properties investigated• breakdown voltage• inverse current
• pre-amplifier: Bergen/Hiroshima design• final decision on rise time and power consumption soon
TESTOUT+12VGNDBIAS-6V
V-6
V-6
V+12
OUTTEST
BIAS
OUT
BIAS
TESTR35100M/2125
C100.1U
R37
22
C90.1U
V+12R36
22
C111U/1608
R38
22
V+12
D1S8664-55
12
R24100M/2125
R2922
C710P
R28
100M/2125
C6
1PC5
1P
R2736K
C40.1U
R2611K
Q6
2SA1462
21
3
Q12SC3735
2
13
D2RD3.9UM
12
C30.1U
R25
5.1K
CN1
53398-0690
123456
R33
47
R34
22
Q42SC3735
2
13
Q32SC3735
2
13
R325.6K
R3111K
R308.2K(4.3K)
Q5
2SC3735
2
13
C2
10NF/3216
GD
S
U1
2SK932
32
1
R23360
Q22SC3735
2
1 3R22
22C81U/1608
May 4, 2004 Photon Detector with PWO and APD / APS Meeting in Denver / Kenta Shigaki 10
- PbWO4 EMC 1st Stage Prototypes -base prototypes – 3×3 assemblies• purposes
• basic properties of PbWO4 crystals• R&D of APD readout system
• components• PbWO4 crystals: Furukawa (Japan) / RI&NC (Belarus)• PMT: Hamamatsu R1450• APD: Hamamatsu S8664• pre-amplifier: Hiroshima ver.1/2
• tests in Japan• Tohoku-LNS (2002); photons at 0.8 – 1.2 GeV• Hiroshima-REFER (2003); electrons at 150 MeV• KEK-PS (planned in May/June, 2004); electrons at 1 – 3 GeV
May 4, 2004 Photon Detector with PWO and APD / APS Meeting in Denver / Kenta Shigaki 11
- PbWO4 EMC Basic Properties -energy resolution σE/E = 2.5 %/√E [GeV] ⊕ 1.3 % with PMTposition resolution σx = 2.3 mm/√E [GeV] with PMTnoise problem with APD at room temperature
coun
ts [a
.u.]
Etotal = 141 MeV
σ/Etotal = 7.3 % = 2.8 % /√E
total energy [MeV]
May 4, 2004 Photon Detector with PWO and APD / APS Meeting in Denver / Kenta Shigaki 12
- PbWO4/APD EMC 2nd Stage Prototype -second stage prototype – 16×16 assembly• purposes
• ALICE-PHOS performance evaluation and final design• components
• PbWO4 crystal: North Crystal (Russia)• APD: Hamamatsu S8664• pre-amplifier: Hiroshima ver.2
• 64 channels in fast timing mode• 192 channels in low power consumption mode
• cooled and stabilized at –25 ± 0.1 ºC• tests at CERN
• PS/SPS (2003): electrons and hadrons at 0.6 – 180 GeV• more tests at PS/SPS (planned in June – November, 2004)
May 4, 2004 Photon Detector with PWO and APD / APS Meeting in Denver / Kenta Shigaki 13
- ALICE-PHOS Performance Evaluation -σE/E = 1.3 %/E [GeV] ⊕ 3.6 %/√E [GeV] ⊕ 1.1 % at – 25 °C
May 4, 2004 Photon Detector with PWO and APD / APS Meeting in Denver / Kenta Shigaki 14
- Neutral Meson Measurement Capabilities -hadron beams at 30 – 70 GeV/ccopper target of 6 cm thicknessinvariant mass resolution σm/m = 7 % for π0, 3 % for η0
π0
η0
η0
May 4, 2004 Photon Detector with PWO and APD / APS Meeting in Denver / Kenta Shigaki 15
- Summary and Outlook -high-granularity high-resolution electromagnetic calorimeter• PbWO4 – scintillating crystal with smallest Moliere radius• APD – compact and magnetic-field resistant readout
properties of key components investigatedseveral prototypes fabricated/tested in Japan/Europe• energy resolution σE/E ~ 3 %/√E [GeV]• clear π0 and η0 peaks observed
first (out of 5) ALICE-PHOS module in 2005• 56×64 Russian PbWO4 crystals + Japanese APD readout system• various R&D/design/production work in progress• assembly/commissioning/tests planned in 2005
ALICE at LHC starting in 2007
May 4, 2004 Photon Detector with PWO and APD / APS Meeting in Denver / Kenta Shigaki 16
- ALICE-PHOS Collaboration -CERNChina (Beijing, Wuhan, Wuhan)Czech Republic (Prague)Germany (Münster)France (Nantes)Japan (Hiroshima)
R.Kohara, K.Hirashita, K.Homma, K.Shigaki, T.Sugitate, D.Toyoda, Y.Tsuchimoto, K.Yokoyama
Norway (Bergen, Oslo)Poland (Warsaw)Russia (Dubna, Moscow, Protovino, Sarov)